@levitanus You have this at the top of your script
Content.makeFrontInterface(600, 500);
Content.makeFrontInterface(633, 300);
Pick one
I don't have scripts/CB.json so I can't do much else to debug.
This works for me though
Content.makeFrontInterface(600, 500);
const var key_low = 0x6000ffff;
Engine.setKeyColour(60, key_low);

@dustbro Add it as a separate script, you can right click the midi processor and connect it as an external script or just copy and paste it in, whatever suits you. Then just link up the controls on your main interface script to the module's controls. BTW the module is licensed as GPL so if you use it your project source code will need to be available under the same license.

@dustbro Here's a full paging system that will work with any number of pages and it's only 31 lines including comments.
HiseSnippet 1219.3ocsWs0aaaCElxIJsVadnEX+.HJ1C1Hco1YsYCHKnN14xL5RhvbZ2.JJBnknrIhLoAEUpMJBv9mr+J6mTGvdYOscnDkkThyEGfom7gmaemK7vickBOZTjPhrpd5rITj0WZ2eFWMp6HBii5sGx5w1tRZDUg5LaBIJh5irrV4PMWqpqhR997q6PBIbOZ9QHz6DLO5OyFyT4m519MrvvCH9zSYiKH8Ka2ySv6JBEw.RVwtIZBw6bxP5wDsXUrQVqsuOSIj8UDEMBjoiveV+QhOxSk+crH1fPplnEpOXnziQcGwB8cyhxHDxZU27XdkzX9qsOh4yleddr+jDF3bMJlCrpTFRqVBRstIHcfHzWafa.dVEf2pov6o188jrIpbNZr8E183JpLf.o8hvJUVTk+ZE6tBPBtZiwjyoGHAh4ZTeqlMeN9UMa1X6ZN0bfjejBeAQhO9sGcl6tGtee7N3M2F+hWb5HJlGOd.UhEA3IPMIBOSDiGQtfpUEjPfifz.EXxogQXB2GOHVo.aVzxFt6fe+G1t34FQyXns3gTEVMpjA0NN2pABItNCTo41XF9GyQMPt95Mp47oZNX3K0.um8APzrjwPppqX7DAGHp+LWsDOaclNOn0v3haSkAJtKflEpzFQZQ4JoHrKILb.zEW2He2NMz4ycihXC4XOCWbPL2SwDbrRXriykoYA27P95hWygwCYbZt9ycScuT.7bH8FFSyyF4IVF2mNUWO0DFWv3EnfjtTRlgqmVFFZToQpgBE.dLFYmLM1Hg9jfL2mkbx78Ow7oXHLR6gRO8NqiZgLnuT8biH3dlIQWOfDFQarchTWV1o5qi34wPbDiOrbLqCg.oXLlRjgLprbeilcYeojwZWc47ztferPQOgWugymbp5boyU4DDrHVF6ERkKhqd5n7VTqd5MxrJrQNXfQ4IRqc+lH4k1lWPPAuGmoNYB0PmOyp0BlYgL2SzCWM.DDUkL65IlYWv8mAhNhoHludzUFYKTRDT7cCzUMwWYLQmjZVhApZmRrLp2ODZ.kIp+H62vECdf91w1bSq4U0+yuF81d6QTD8XbSNAxSSnRESWNr1idA7lX5P8p16QiNWIljjzLCWfRVpeqkMxW2Hl3V3YX8uahll6vuo8rhDej4qFgrrs9GfbDkMbjRS82.kUkq6i6rzLs3C24d5O+01iIS0VVSMgHAiVv5yAJpvg12iRYA2sUA28660994iGcGotVOrT2EYWZfW7st4PZAsWEbWuh4u92X.0pT.s18oGLoP7GPonP7bXaEcpwpvXuVHIwmINTJhmjcG9ZosayKsJ4EaKF3iRdXyq4gHX8fdbyliPpCc80ZfkqD9wgDU4MtzqVZX.y7JsZid8EdDSMq3ctkXMrlKbMrENR6dB2mZ6xTdiVLdqr.7puJ9+LdMK0Vyd+f.pmJGrqZevu8P2fcIfxuHhUv6rGQTRltu433w8g858n.R352U0sPUzCaSoalMJoOk6mP7uvmgYKMskgYqLlnwDOo3LylF50lebxI.l3I+igp1Goowymwqw8XXW9y77zIhuEP9h0XykViuao03kKsFuZo0XqkViueo03GtEMz+wociUhwoWKfCb2O4sQKq84DnqJoCD8e5FL6VC

I think it's a mistake in the API doc - it's created automatically by using the inheritance hierarchy of the C++ classes and this one might slipped in to the wrong place. Content.setPropertiesFromJSON() is definitely the go-to option.
However, the missing link might be a method like Control.getName() so you can call it without having to store the String name somewhere.

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